Joint Laboratory of Guangdong Province and Hong Kong Regions on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China.
State Key Laboratory of Biocontrol/Key Laboratory of Aquatic Product Safety, Ministry of Education, The School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, Guangdong Province, PR China.
Fish Shellfish Immunol. 2018 Jun;77:91-99. doi: 10.1016/j.fsi.2018.03.039. Epub 2018 Mar 19.
Bruton's tyrosine kinase (BTK) is a Tec-family tyrosine kinase and plays a crucial role in B cell antigen receptor (BCR) signal pathway. Mutations in humans and mice BTK gene results in X-linked agammaglobulinemia (XLA) and X-linked immunodeficiency (XLD), respectively. To study the function of BTK in teleost, we cloned a BTK gene from orange-spotted grouper. Homology analysis showed that the grouper BTK (EcBTK) had a high amino acid identity with other vertebrates (63%-92%) and shared the highest amino acid identity with ballan wrasse Labrus bergylta BTK. EcBTK comprises a Bruton's tyrosine kinase pleckstrin homology (PH) domain, a Tec homology (TH) domain, a Src homology 3 (SH3) domain, a Src homology 2 (SH2) domain and a Protein Kinases, catalytic (PKc) domain. Tissue distribution analysis showed that EcBTK was mainly expressed in immune organs. EcBTK was uniform distributed throughout the cytoplasm of transfected HEK293T cells and overexpression of EcBTK slightly down-regulates NF-κB activity. Ibrutinib treatment can reduce the phosphorylation level of grouper's BTK. In groupers infected with Cryptocaryon irritans, up-regulation of EcBTK were not seen in the early stage of infected skin and gill until days 14-21. The phosphorylation level of grouper BTK was significantly increased in infected skin and gill.
布鲁顿酪氨酸激酶（BTK）是 Tec 家族酪氨酸激酶，在 B 细胞抗原受体（BCR）信号通路中发挥关键作用。人类和小鼠 BTK 基因突变分别导致 X 连锁无丙种球蛋白血症（XLA）和 X 连锁免疫缺陷（XLD）。为了研究 BTK 在硬骨鱼类中的功能，我们从鞍带石斑鱼中克隆了一个 BTK 基因。同源性分析表明，石斑鱼 BTK（EcBTK）与其他脊椎动物具有很高的氨基酸同一性（63%-92%），与蓝颊神仙鱼 Labrus bergylta BTK 的氨基酸同一性最高。EcBTK 包含一个布鲁顿酪氨酸激酶pleckstrin 同源（PH）结构域、一个 Tec 同源（TH）结构域、一个Src 同源 3（SH3）结构域、一个Src 同源 2（SH2）结构域和一个蛋白激酶，催化（PKc）结构域。组织分布分析表明，EcBTK 主要在免疫器官中表达。EcBTK 在转染的 HEK293T 细胞的细胞质中均匀分布，过表达 EcBTK 会略微下调 NF-κB 活性。伊布替尼处理可降低鱼类 BTK 的磷酸化水平。在感染 Cryptocaryon irritans 的鞍带石斑鱼中，在感染皮肤和鳃的早期阶段（第 14-21 天），未见 EcBTK 的上调。感染皮肤和鳃中鱼类 BTK 的磷酸化水平显著增加。
